00:01
Hi, i'm david and i'm here to help you.
00:02
I'm seeing your question.
00:03
Now let me break up your question here.
00:21
Now in this question we are going to discuss about the normal distribution.
00:25
Let me remind you that if you have the x that followed by the normal, with the mean and the mean and the standard deviation, and if we take the x minus the mean over standard deviation, we obtain the standard normal.
00:37
Also, if we take the x bar we minus the mean over standard deviation, we need to divide by square of n.
00:43
In another term 10 standard normal.
00:46
In this question here, we're given the x will be the level of the nitrous oxidite and the organic gas x, we will follow by the normal, with the mean equal to the 80, standard division equal to the 4, we're given the n equal to the 25.
01:04
Now we need to find the level end such that the probability of the x bar greater than l here it will be only the z -1 -0 -1.
01:14
Now to find the level l, first of all we need to convert the x into the z by applying the formula for the x bar.
01:22
So we need to take the value l, we minus the mean at over the standard division the 1 square litem the n and then equal to the z1 01.
01:33
Now for the 0 -01 we need to bring it, we have to convert it into the form on the probability.
01:39
To do it, we need to bring up the z1...